P1a topic 9 Electrical energy

Learning objectives There is a variety of ways we can produce electricity. Electrical quantities can be measured. Keywords: ampere-hours (amp-hours) battery battery capacity (ampere-hours) current (amperes/amps/A, milliamps/mA) rechargeable voltage (volts/V, millivolts/mV)

Learning outcomes describe and compare sources of direct current, including batteries, solar cells demonstrate understanding that a battery has a stated capacity in terms of amp-hours and use this to predict the number of hours a battery should last when supplying a given current investigate practically or otherwise the voltage and current output, and the advantages and disadvantages of different batteries (both dry cell or rechargeable), including considerations of their cost, performance and impact on the environment be able to plot data graphically, intepret trends and describeAdvantages of using data logging

Where do you get your energy from when you are on the move? I pod Mp4 players DVD players Mobile phones What keeps them going?

Which is which and how do we choose? Popular Alkaline Procell alkaline batteries provide the same performance and quality as DURACELL batteries delivering outstanding performance and reliability. Major advantages are: Long lasting power providing superior dependability - even after five years of storage Lasts up to five times longer than super heavy duty batteries Long service life at high drain discharges Operates reliably in temperature extremes of -20 degrees C to 54 degrees C Date coded to ensure freshness Economical bulk packaging for professional applications Contains no added mercury Duracell Ultra Duracell Ultra alkaline batteries are specifically designed for today's high-tech devices that push the limits of existing alkaline battery performance. Lasts up to 50% longer than Energizer's advanced design batteries in high-tech devices. Available in AA, AAA, C, D and 9 Volt sizes, the sizes most commonly used in high-tech devices.

Lantern Batteries Procell alkaline lantern batteries last up to twice as long as super heavy- duty batteries and provide an extra measure of leakage resistance for critical applications. Procell alkaline lantern batteries offer: A long shelf life Reliable performance at temperature extremes Date coding to ensure freshness No added mercury Photo/Electronic Lithium Duracell's lithium/manganese dioxide batteries represent one of the latest advances in primary battery technology. For applications with a high current pulse (e.g. photoflash) and continuous drain, Duracell offers high rate 3 and 6 volt lithium batteries. All Duracell lithium batteries provide: High energy density and excellent rate capability Up to 4 times the power of alkaline batteries Wide operating temperature range (-40 degrees F to 140 degrees F) and superior low temperature performance Excellent shelf life (0.5 percent capacity loss per year at room temperature)

What were the differences? Would you choose these cells or batteries to provide your energy? Why?

Differences: Materials – some contain toxic metals – some contain acids or alkalis Voltage – each device needs a particular voltage so you may need to use two or three cells together Current – each device needs a certain current Long lasting ? Do you want to change them over frequently? Do they need to keep up the delivery over a long time? Rechargeable? The material lasts a long time, so less environmental damage but the energy needs to be put back in frequently.

charge capacity Complete this chart to show what will happen

What happens after use? How long does take to run down?

Energy capacity Cells store chemical energy and transfer it as electrical energy. We have seen that we can compare cells by charge capacity ….. But we can also compare the energy stored. Energy = power x time So the energy stored is the power output x time available. Energy has the units of joules but power is measured in watts, while time could be in seconds, hours or even days or years. On board space missions, energy capacity has to be in W hours or W years as the cells or batteries cannot be replaced, though they can be recharged.

Energy capacity If given as W h then is a measure of energy capacity If as W h/Kg then a measure of energy per mass of battery If as W h/cm 3 then a measure of energy per volume of battery

Using Graphs

Using a data logger Advantages: Plots graphs automatically Avoids boredom o taking lots of readings over many hours Can get more readings in a set time if sampling time is a short interval

Why recycle? Apart from using up suitable landfill sites, most batteries contain metals such as lead, cadmium and mercury. If the batteries are not disposed of properly, these metals may leak into the ground, contributing to soil and water pollution. Some of the metals can accumulate in fish, and make them unfit for humans to eat. The metals recovered from batteries can be used again. All metals are a limited resource, and we will eventually run out of them in the same way that we will eventually run out of fossil fuels (although there is no immediate problem with metals).

How to Encourage Recycling Tax Ban Grants Promote Research and development

A Which metals do different types of batteries contain? B Which metals can be recovered in recycling, and how is this done for different metals? C How can you recycle batteries? Is there a recycling scheme in your area? D What does the law say about recycling batteries? E What can you do to help with the problems of pollution from batteries, and to cut down the amount of energy you use from batteries? What arguments would you use for recycling? waste cells